Dyeing and printing process



Patented Nov. 8, 1932 UNITED STATES PATEN-T OFFICE JULES MARTIN DIT GAUDIT, F PARIS, FRANCE DYEING AND PRINTING PROCESS No Drawing. Application filed J uly 10, 1930, Serial No. 467,133, and in France August 2, 1929.

When acid or basic dye-stuifs, alizarin dyestuffs or mordant dye-stuffs are dyed or printed on materials or fibres, it is necessary,

for utilizing the'properties of the dye-stuffs and giving them corresponding fastness, to treat them in a bath which is nearly always hot, most frequently at boiling point, sometimes by adding sulphate of soda, or to fix them in water vapour either in the open air,

or under pressure during a more or less long period of time.

Now, when dyeing or printing any materials in general, or moreparticularly animal fibres, the applicant has found that the dyeing baths or printing pastes presented new conditions facilitating all the operations when the acidity of the bath was obtained by means of formic acid starting from a certain proportion which up to now has never been thought of.

In fact, the use of formic acid is known in certain dyeing operations, but this acid is used only by substitution for other mineral or-organic acids for acidifying the baths; the

2 proportion which is then used scarcely reaches about 6% of the weight of the fibre or material to be dyed, and the proportion concerning the bath in which it is dissolved is still much smaller, since this bath always represents at least 30 to times and often up to 100 times and more the Weight of the materials to be dyed. g

It is also known that for printing purposes, use is sometimes made, although rare- 35 1y, of formic acid substituted for another organic acid for its acid function, but the proportion added to the paste is always maintained between 30 and 50 grams per litre or kilogram, that is to say less than 5%.

The inventor has found, on the contrary, that formic acid used under the high concentration hereinafter indicated and much superior to any proportions employed heretofore, produces new efiects when operating under certain conditions, this having for result to completely modify all the dyeing operations actuallyeffected; this results from the physico-chemical action of this articular acid, in the conditions considere on the organic constituents of the materials to be dyed, action which satisfactorily combines with that exerted by'formic acid in the usual processes of fixation of dye-stuffs.

The present invention resulting from these observations consists in preparing at ordi nary temperature either pastes which, after printing will not necessitate any vaporization, (by previously dissolving the dye-v stuffs in formic acid,- so that the final proportion of formic acid in a combined or,v

.free condition, in this solution, is always at 7 free or combined condition.

The percentage of free or combined formic acid in the bath between the limits indicated will vary according to the nature ,of the operations to be effected: dyeing of piece goods,-dyeing of fleece-Wool or of combed wool, or of wool in hanks,-dyeing of silk in the piece or of silkin skeins,printing or dyeing of any materialsto be dyed.

By formic acid of 80% strengthis meant commercial acid. 1

Examples of preparation of dyeing baths I or of printing pastes:

' 1-Dyeing.In an aqueous bath containiI 1g 20% (by volume of thebath) of formic acid to which is added in variable quantity according to the shade to be obtainedan acid yellow, or anacid blue, or an acid red, or

their mixture, any desired range of shades is obtained in the cold state.

2Printing.'In a printing paste containing 20% by volume of formic acid, is added an acid yellow, or an acid'red,orfai1 acid blue, or their mixtures, any desired range of shades is obtained in the cold state. 3Printing.In a printing paste; containing 20% by volume of formic acid is added to one or more aliza'rin' or mord'ant dye-stuffs with their metallic mordants; printing is effected without vaporization being necessary, the fixation being effected in the cold state.

These operations thus effected in the cold state and rapidly, producing new dyeing and rinting effects, are sometimes nearly instanneously obtained; it is then necessary, in practice, to moderate the development of the colours thus fixed; in these conditions, by remaining in the basic proportions above mentioned for the use of formic acid, the work is facilitated by retarding the dyeing and printing in the cold state by addition of a given'proportion of various organic acids.

Claims:

1. Process for dyeing or printing on any fibres, which consists in applying on the said fibres a mixture comprising a dye-stuff usable in acid bath, water and 10 to 50% by volume of commercial formic acid in the cold state.

2. Process for dyeing or printing in the 7 cold state on any fibres, which consists in applying on the said fibres a mixture comprising a dye-stuff usable in acid bath, Wator and 10 to 50% by volume of commercial formic acid in the cold state and an organic acid capable of retarding the colouring action of the mixture.

3. A mixture for dyeing or printin any fibres, comprising Water, a dye-stuif usa 1e in acid bath and 10 to 50% by volume of'commercial formic acid.

4. A mixture for dyeing or printing any fibres, comprising water, a dye-stuff usable in acid bath, 10 to 50% by volume of commercial formic acid and an organic acid capable of retarding the colouring action of the mixture.

In testimony whereof. I have hereunto af- 40 fixed my signature.

J ULES MARTIN DIT GAUDIT. 

